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1.
BMC Neurol ; 21(1): 154, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33836684

RESUMO

BACKGROUND: The cortical microvascular cerebral blood flow response (CBF) to different changes in head-of-bed (HOB) position has been shown to be altered in acute ischemic stroke (AIS) by diffuse correlation spectroscopy (DCS) technique. However, the relationship between these relative ΔCBF changes and associated systemic blood pressure changes has not been studied, even though blood pressure is a major driver of cerebral blood flow. METHODS: Transcranial DCS data from four studies measuring bilateral frontal microvascular cerebral blood flow in healthy controls (n = 15), patients with asymptomatic severe internal carotid artery stenosis (ICA, n = 27), and patients with acute ischemic stroke (AIS, n = 72) were aggregated. DCS-measured CBF was measured in response to a short head-of-bed (HOB) position manipulation protocol (supine/elevated/supine, 5 min at each position). In a sub-group (AIS, n = 26; ICA, n = 14; control, n = 15), mean arterial pressure (MAP) was measured dynamically during the protocol. RESULTS: After elevated positioning, DCS CBF returned to baseline supine values in controls (p = 0.890) but not in patients with AIS (9.6% [6.0,13.3], mean 95% CI, p < 0.001) or ICA stenosis (8.6% [3.1,14.0], p = 0.003)). MAP in AIS patients did not return to baseline values (2.6 mmHg [0.5, 4.7], p = 0.018), but in ICA stenosis patients and controls did. Instead ipsilesional but not contralesional CBF was correlated with MAP (AIS 6.0%/mmHg [- 2.4,14.3], p = 0.038; ICA stenosis 11.0%/mmHg [2.4,19.5], p < 0.001). CONCLUSIONS: The observed associations between ipsilateral CBF and MAP suggest that short HOB position changes may elicit deficits in cerebral autoregulation in cerebrovascular disorders. Additional research is required to further characterize this phenomenon.


Assuntos
Pressão Arterial , Estenose das Carótidas/fisiopatologia , Circulação Cerebrovascular , Decúbito Dorsal/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo/fisiologia , Pressão Sanguínea , Isquemia Encefálica/fisiopatologia , Estudos de Casos e Controles , Feminino , Decúbito Inclinado com Rebaixamento da Cabeça/fisiologia , Hemodinâmica , Homeostase , Humanos , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral/fisiopatologia
2.
Medicine (Baltimore) ; 100(3): e24411, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33546085

RESUMO

BACKGROUND: Superb microvascular imaging (SMI) is a new ultrasound vascular imaging technology, which uses a new Doppler algorithm, it has the characteristics of high sensitivity and high resolution to detect low velocity blood flow; it is easier to detect microvessels with low-velocity flow compared with color Doppler flow imaging in theory; and it can image the microvessels of the lesion without angiography.[1] Previous studies showed that SMI can detect tumor neovascularization to differentiate benign from malignant focal liver lessions (FLLs). However, the results of these studies have been contradictory with low sample sizes. This meta-analysis tested the hypothesis that SMI is accurate in distinguishing benign and malignant FLLs. METHODS: We will search PubMed, Web of Science, Cochrane Library, and Chinese biomedical databases from their inceptions to the November 30, 2020, without language restrictions. Two authors will independently carry out searching literature records, scanning titles and abstracts, full texts, collecting data, and assessing risk of bias. Review Manager 5.2 and Stata14.0 software will be used for data analysis. RESULTS: This systematic review will determine the accuracy of SMI in the differential diagnosis between benign and malignant FLLs. CONCLUSION: Its findings will provide helpful evidence for the accuracy of SMI in the differential diagnosis between benign and malignant FLLs. SYSTEMATIC REVIEW REGISTRATION: INPLASY2020120081.


Assuntos
Protocolos Clínicos , Fígado/anormalidades , Fígado/diagnóstico por imagem , Ultrassonografia/métodos , Ultrassonografia/normas , Velocidade do Fluxo Sanguíneo/fisiologia , Humanos , Metanálise como Assunto , Revisões Sistemáticas como Assunto
3.
J Neurointerv Surg ; 13(4): 324-330, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33593797

RESUMO

BACKGROUND: There are no reports that describe complete flow control using concurrent transient rapid ventricular pacing or intravenous (IV) adenosine and afferent arterial balloon flow arrest to aid transvenous embolization of cerebral arteriovenous malformations (AVM). We describe our experience with the use of this technique in patients undergoing transvenous AVM embolization. METHODS: Consecutive patients in whom transvenous embolization was attempted at our institute between January 2017 and July 2019 were included. Anatomical AVM features, number of embolization stages, technique of concurrent transient rapid ventricular pacing and afferent arterial balloon flow arrest, complications, and clinical and radiological outcomes were recorded and tabulated. RESULTS: Transvenous AVM embolization was attempted in 12 patients but abandoned in two patients for technical reasons. Complete embolization was achieved in 10 patients, five of whom had infratentorial AVMs. All 10 had a single primary draining vein. Rapid ventricular pacing was used in nine cases; IV adenosine injection was used in one case to achieve cardiac standstill. Complete AVM nidus obliteration was achieved with excellent neurologic outcome in nine cases, with transvenous embolization alone in two cases, and with staged transarterial followed by transvenous embolization in the others. Two patients developed hemorrhagic complications intraprocedurally. One patient was managed conservatively and the other operatively with AVM excision and hematoma evacuation; both made an excellent recovery without any neurologic deficits at 3 months. CONCLUSION: Complete flow control using concurrent transient rapid ventricular pacing with afferent arterial balloon flow arrest technique is safe and feasible for transvenous embolization of select AVMs.


Assuntos
Adenosina/administração & dosagem , Fístula Arteriovenosa/terapia , Oclusão com Balão/métodos , Velocidade do Fluxo Sanguíneo/fisiologia , Embolização Terapêutica/métodos , Malformações Arteriovenosas Intracranianas/terapia , Administração Intravenosa , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Fístula Arteriovenosa/diagnóstico por imagem , Fístula Arteriovenosa/fisiopatologia , Feminino , Seguimentos , Humanos , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Malformações Arteriovenosas Intracranianas/fisiopatologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
4.
BMC Pregnancy Childbirth ; 21(1): 158, 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33622280

RESUMO

BACKGROUND: Fetal superior vena cava (SVC) is essentially the single vessel returning blood from the upper body to the heart. With approximately 80-85% of SVC blood flow representing cerebral venous return, its interrogation may provide clinically relevant information about fetal brain circulation. However, normal reference values for fetal SVC Doppler velocities and pulsatility index are lacking. Our aim was to establish longitudinal reference intervals for blood flow velocities and pulsatility index of the SVC during the second half of pregnancy. METHODS: This was a prospective study of low-risk singleton pregnancies. Serial Doppler examinations were performed approximately every 4 weeks to obtain fetal SVC blood velocity waveforms during 20-41 weeks. Peak systolic (S) velocity, diastolic (D) velocity, time-averaged maximum velocity (TAMxV), time-averaged intensity-weighted mean velocity (TAMeanV), and end-diastolic velocity during atrial contraction (A-velocity) were measured. Pulsatility index for vein (PIV) was calculated. RESULTS: SVC blood flow velocities were successfully recorded in the 134 fetuses yielding 510 sets of observations. The velocities increased significantly with advancing gestation: mean S-velocity increased from 24.0 to 39.8 cm/s, D-velocity from 13.0 to 19.0 cm/s, and A-velocity from 4.8 to 7.1 cm/s. Mean TAMxV increased from 12.7 to 23.1 cm/s, and TAMeanV from 6.9 to 11.2 cm/s. The PIV remained stable at 1.5 throughout the second half of pregnancy. CONCLUSIONS: Longitudinal reference intervals of SVC blood flow velocities and PIV were established for the second half of pregnancy. The SVC velocities increased with advancing gestation, while the PIV remained stable from 20 weeks to term.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Coração Fetal/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Veia Cava Superior/fisiologia , Feminino , Coração Fetal/diagnóstico por imagem , Humanos , Gravidez , Segundo Trimestre da Gravidez , Terceiro Trimestre da Gravidez , Estudos Prospectivos , Valores de Referência , Ultrassonografia Doppler , Ultrassonografia Pré-Natal , Veia Cava Superior/diagnóstico por imagem
5.
PLoS One ; 16(1): e0244795, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33412561

RESUMO

BACKGROUND: Impaired perfusion indices signal potential microvascular dysfunction preceding atherosclerosis and other cardiometabolic pathologies. Post-occlusive reactive hyperemia (PORH), a vasodilatory response following a mechanically induced ischemia, is a transient increase in perfusion and can assess microvascular function. The greatest blood flow change corresponding to the first minute of hyperemia (represented by time-to-peak, hyperemic velocity, AUC within 1st min) has been shown to indicate microvascular dysfunction. However, the reproducibility of these temporal kinetic indices of the PORH response is unknown. Our aim was to examine the inter- and intra-day reproducibility and standardization of reactive hyperemia, with emphasis on the kinetic indices of PORH, using laser speckle contrast imaging (LSCI) technique. METHODS AND RESULTS: Seventeen healthy adults (age = 24 ± 3 years) completed three PORH bouts over two lab visits. LSCI region of interest was a standardized 10 cm region on the dominant ventral forearm. A 5-min brachial artery occlusion period induced by inflating an arm cuff to 200 mmHg, preceded a 4-min hyperemic period. Inter- and intra-day reliability and reproducibility of cutaneous vascular conductance (LSCI flux / mean arterial pressure) were determined using intraclass correlation (ICC) and coefficient of variation (CV%). Maximal flow and area under the curve standardized to zero perfusion showed intra- and inter-day reliability (ICC > 0.70). Time to maximal flow (TMF) was not reproducible (inter-day CV = 18%). However, alternative kinetic indices such as 1-min AUC and overshoot rate-of-change (ORC), represented as a piecewise function (at 5s, 10s, 15s, and 20s into hyperemia), were reproducible (CV< 11%). Biological zero was a reliable normalization point. CONCLUSION: PORH measured with LSCI is a reliable assessment of microvascular function. However, TMF or its derived hyperemic velocity are not recommended for longitudinal assessment. Piecewise ORC and 1-min AUC are reliable alternatives to assess the kinetic response of PORH.


Assuntos
Hiperemia/diagnóstico por imagem , /métodos , Adulto , Área Sob a Curva , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Antebraço/irrigação sanguínea , Voluntários Saudáveis , Hemodinâmica , Humanos , Isquemia/fisiopatologia , Fluxometria por Laser-Doppler/métodos , Masculino , Microcirculação/fisiologia , Fluxo Sanguíneo Regional/fisiologia , Reprodutibilidade dos Testes , Vasodilatação/fisiologia , Adulto Jovem
6.
Pediatr Surg Int ; 37(2): 197-203, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33388956

RESUMO

PURPOSE: The optimal timing of surgery for congenital diaphragmatic hernia (CDH) is controversial. We aimed to validate our protocol for the timing of CDH repair using the quantified patent ductus arteriosus (PDA) flow pattern. METHODS: This retrospective comparative study analyzed patients with a prenatal diagnosis of isolated CDH between 2007 and 2020. We defined the "LR ratio" as the percentage of velocity-time integral (VTI) of the left-to-right flow of PDA against overall VTI on echocardiography. Since 2010, we followed the decision criterion of performing surgery when LR ratio of > 50% has been achieved in the patients (protocol group). The protocol group (2010-2020) was compared with the historical control group (2007-2009). RESULTS: The average age at surgery was 104.1 ± 175.9 and 37.3 ± 30.6 h in the control and protocol groups, respectively (p = 0.11). Survival rate (88.9% vs. 95.0%, p = 0.53) and the rate of worsening of pulmonary hypertension within 24 h after surgery (22.2% vs. 10.0%, p = 0.57) were not different between the groups. The protocol group had a significantly shorter duration of tracheal intubation (26.9 ± 21.1 vs. 13.3 ± 9.5 days, p = 0.03). CONCLUSION: Our decision criterion might have the advantage of facilitating early and safe surgery for patients with CDH.


Assuntos
Anormalidades Múltiplas , Velocidade do Fluxo Sanguíneo/fisiologia , Permeabilidade do Canal Arterial/fisiopatologia , Hérnias Diafragmáticas Congênitas/cirurgia , Herniorrafia/métodos , Pré-Escolar , Permeabilidade do Canal Arterial/diagnóstico , Ecocardiografia , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Duração da Cirurgia , Estudos Retrospectivos
7.
Biomed Res Int ; 2021: 8239326, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33490277

RESUMO

Method: The FSI model, based on MRI data of an atherosclerosis patient, was used to simulate the deformations of the plaque and lumen during the process of two kinds of typical cSMT (the high-speed, low-amplitude spinal manipulation and the cervical rotatory manipulation). The biomechanical parameters were recorded, such as the highest wall shear stress (WSS), the maximum plaque wall stress (PWS), the wall tensile stress (Von mises stress, VWTS), and the strain. Result: The max_WSS was 33.77 kPa in the most extensive deformation. The highest WSS region on the plaque surface was also the highest PWS region. The max_PWS in a 12% stretch was 55.11 kPa, which was lower than the rupture threshold. The max_VWTS of the cap in 12% stretch which approached the fracture stress level was 116.75 kPa. Moreover, the vessel's max_VWTS values in 10% and 12% stretch were 554.21 and 855.19 kPa. They were higher than the fracture threshold, which might cause media fracture. Meanwhile, the 7% stretched strain was 0.29, closed to the smallest experimental green strains at rupture. Conclusion: The carotid arteries' higher stretch generated the higher stress level of the plaque. Cervical rotatory manipulation might cause plaque at a high risk of rupture in deformation after 12% stretch and more. Lower deformation of the plaque and artery caused by the high-speed, low-amplitude spinal manipulation might be safer.


Assuntos
Doenças das Artérias Carótidas , Vértebras Cervicais/fisiologia , Imageamento Tridimensional/métodos , Manipulação da Coluna/efeitos adversos , Modelos Cardiovasculares , Idoso , Velocidade do Fluxo Sanguíneo/fisiologia , Artérias Carótidas/diagnóstico por imagem , Artérias Carótidas/fisiopatologia , Doenças das Artérias Carótidas/diagnóstico por imagem , Doenças das Artérias Carótidas/fisiopatologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Medição de Risco , Ruptura
8.
J Ethnopharmacol ; 264: 113235, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32777518

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: DG is a herbal formula, containing the root of Salvia miltiorrhiza Bunge (Danshen) and the root of Pueraria lobate (Willd.) Ohwi (Gegen), has a history of usage in China for cardiovascular protection and anti-atherosclerosis. AIM OF THE STUDY: The present study aims to determine the beneficial effect of DG on the hind-limb ischemia rat model which mimics peripheral arterial disease (PAD) and its vasodilative effect on isolated femoral artery. MATERIALS AND METHODS: The vasodilatory effects were assessed by contractile responses to DG in the isolated femoral artery and its underlying mechanisms were evaluated by the involvement of endothelium, potassium channel and calcium channel. For hind-limb ischemia study, treatment outcomes were assessed by evaluating hind-limb blood flow, functional limb recovery, muscle histology and angiogenesis. RESULTS: Our results demonstrated positive dose-dependent vasodilatory response to DG via an endothelium-independent mechanism that involved inwardly rectifying K+ channels and Ca2+ channels. We also demonstrated significant improvement in blood perfusion and micro-vessel density in the ischemic limb and positive effects in functional limb recovery. CONCLUSION: In conclusion, our study supported the potential use of DG as a novel treatment for symptomatic PAD.


Assuntos
Marcha/efeitos dos fármacos , Doença Arterial Periférica/tratamento farmacológico , Extratos Vegetais/uso terapêutico , Pueraria , Salvia miltiorrhiza , Vasodilatação/efeitos dos fármacos , Animais , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Velocidade do Fluxo Sanguíneo/fisiologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Marcha/fisiologia , Membro Posterior/irrigação sanguínea , Membro Posterior/efeitos dos fármacos , Masculino , Técnicas de Cultura de Órgãos , Doença Arterial Periférica/fisiopatologia , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Ratos , Ratos Sprague-Dawley , Vasodilatação/fisiologia
9.
Sci Rep ; 10(1): 22257, 2020 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-33335236

RESUMO

We aimed to clarify clinical implications of intrarenal hemodynamics assessed by intrarenal Doppler ultrasonography (IRD) and their prognostic impacts in heart failure (HF). We performed a prospective observational study, and examined IRD and measured interlobar renal artery velocity time integral (VTI) and intrarenal venous flow (IRVF) patterns (monophasic or non-monophasic pattern) to assess intrarenal hypoperfusion and congestion in HF patients (n = 341). Seven patients were excluded in VTI analysis due to unclear imaging. The patients were divided into groups based on (A) VTI: high VTI (VTI ≥ 14.0 cm, n = 231) or low VTI (VTI < 14.0 cm, n = 103); and (B) IRVF patterns: monophasic (n = 36) or non-monophasic (n = 305). We compared post-discharge cardiac event rate between the groups, and right-heart catheterization was performed in 166 patients. Cardiac index was lower in low VTI than in high VTI (P = 0.04), and right atrial pressure was higher in monophasic than in non-monophasic (P = 0.03). In the Kaplan-Meier analysis, cardiac event rate was higher in low VTI and monophasic groups (P < 0.01, respectively). In the Cox proportional hazard analysis, the combination of low VTI and a monophasic IRVF pattern was a predictor of cardiac events (P < 0.01). IRD imaging might be associated with cardiac output and right atrial pressure, and prognosis.


Assuntos
Insuficiência Cardíaca/diagnóstico por imagem , Rim/fisiopatologia , Prognóstico , Idoso , Biomarcadores/metabolismo , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/fisiopatologia , Testes de Função Cardíaca , Hemodinâmica , Humanos , Estimativa de Kaplan-Meier , Rim/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Ultrassonografia Doppler
10.
J Clin Neurosci ; 82(Pt A): 115-121, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33317718

RESUMO

Continuous measurement of cerebral blood flow velocity (CBFV) of the middle cerebral artery (MCA) using transcranial Doppler (TCD) and arterial blood pressure (ABP) monitoring enables assessment of cerebrovascular haemodynamics. Further indices describing cerebrovascular function can be calculated from ABP and CBFV, such as the mean index (Mxa) of cerebrovascular autoregulation, the 'time constant of the cerebral arterial bed' (tau), the 'critical closing pressure' (CrCP) and a 'non-invasive estimator of ICP' (nICP). However, TCD is operator-dependent and changes in angle and depth of MCA insonation result in different readings of CBFV. The effect of differing CBFV readings on the calculated secondary indices remains unknown. The aim of this study was to investigate variation in angle and depth of MCA insonation on these secondary indices. In eight patients continuous ABP and ipsilateral CBFV monitoring was performed using two different TCD probes, resulting in four simultaneous CBFV readings at different angles and depths per patient. From all individual recordings, the K-means clustering algorithm was applied to the four simultaneous longitudinal measurements. The average ratios of the between-clusters, sum-of-squares and total sum-of-squares were significantly higher for CBFV than for the indices Mxa, tau and CrCP (p < 0.001, p = 0.007 and p = 0.016) but not for nICP (p = 0.175). The results indicate that Mxa, tau and CrCP seemed to be not affected by depth and angle of TCD insonation, whereas nICP was.


Assuntos
Algoritmos , Circulação Cerebrovascular/fisiologia , Hemodinâmica/fisiologia , Interpretação de Imagem Assistida por Computador/métodos , Ultrassonografia Doppler Transcraniana/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Homeostase/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiologia
11.
PLoS One ; 15(9): e0238946, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956397

RESUMO

BACKGROUND: The origin of low frequency cerebral hemodynamic fluctuations (CHF) in the resting state remains unknown. Breath-by breath O2-CO2 exchange ratio (bER) has been reported to correlate with the cerebrovascular response to brief breath hold challenge at the frequency range of 0.008-0.03Hz in healthy adults. bER is defined as the ratio of the change in the partial pressure of oxygen (ΔPO2) to that of carbon dioxide (ΔPCO2) between end inspiration and end expiration. In this study, we aimed to investigate the contribution of respiratory gas exchange (RGE) metrics (bER, ΔPO2 and ΔPCO2) to low frequency CHF during spontaneous breathing. METHODS: Twenty-two healthy adults were included. We used transcranial Doppler sonography to evaluate CHF by measuring the changes in cerebral blood flow velocity (ΔCBFv) in bilateral middle cerebral arteries. The regional CHF were mapped with blood oxygenation level dependent (ΔBOLD) signal changes using functional magnetic resonance imaging. Temporal features and frequency characteristics of RGE metrics during spontaneous breathing were examined, and the simultaneous measurements of RGE metrics and CHF (ΔCBFv and ΔBOLD) were studied for their correlation. RESULTS: We found that the time courses of ΔPO2 and ΔPCO2 were interdependent but not redundant. The oscillations of RGE metrics were coherent with resting state CHF at the frequency range of 0.008-0.03Hz. Both bER and ΔPO2 were superior to ΔPCO2 in association with CHF while CHF could correlate more strongly with bER than with ΔPO2 in some brain regions. Brain regions with the strongest coupling between bER and ΔBOLD overlapped with many areas of default mode network including precuneus and posterior cingulate. CONCLUSION: Although the physiological mechanisms underlying the strong correlation between bER and CHF are unclear, our findings suggest the contribution of bER to low frequency resting state CHF, providing a novel insight of brain-body interaction via CHF and oscillations of RGE metrics.


Assuntos
Circulação Cerebrovascular/fisiologia , Taxa Respiratória/fisiologia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Encéfalo/fisiologia , Dióxido de Carbono/sangue , Feminino , Voluntários Saudáveis , Hemodinâmica/fisiologia , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Artéria Cerebral Média/fisiologia , Oxigênio/sangue , Pressão Parcial , Respiração , Descanso/fisiologia , Ultrassonografia Doppler Transcraniana/métodos , Vasodilatação/fisiologia
12.
Am J Cardiol ; 133: 139-147, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32838928

RESUMO

Ventricular septal defects (VSDs) have recently demonstrated poorer functional outcome with disrupted ventricular contractility during exercise in young patients. It is not known whether this will change with age. Therefore, echocardiography was performed in older patients with congenital VSDs, either surgically closed or unrepaired and all without Eisenmenger physiology, to compare functional outcomes with healthy peers. Transthoracic echocardiography was performed at rest and during supine bicycle exercise, with tissue velocity Doppler for assessment of primary end points: isovolumetric acceleration and systolic velocities. In total, 30 surgically closed VSDs (51 ± 8 years) with 30 healthy controls (52 ± 9 years) and 30 unrepaired VSDs (55 ± 12 years) with 30 matched controls (55 ± 10 years) were included. Surgical patients displayed lower right ventricular (RV) systolic and early diastolic-filling velocities compared with controls, p <0.01, lower tricuspid annular plane systolic excursion (17.8 ± 5 vs 22.7 ± 3mm, p <0.01) and lower fractional area change (37.8 ± 6 vs 46.4% ± 7%, p <0.01). Unrepaired VSDs also had lower RV fractional area change than matched controls (39.9 ± 7 vs 48.4% ± 7%, p <0.01). Both patient groups had more tricuspid regurgitation and larger RV outflow tract dimensions than controls, p <0.01. During exercise, isovolumetric acceleration and systolic velocities were lower in both patient groups compared with controls, with the difference increasing with workload level. In conclusion, adults in their mid-50s with surgically closed or unrepaired VSDs have abnormal RV function at rest, with even more pronounced differences during exercise. These results suggest that a VSD, whether repaired early or considered hemodynamically insignificant, is not a benign lesion and continuous follow-up of adults is warranted.


Assuntos
Débito Cardíaco/fisiologia , Comunicação Interventricular/fisiopatologia , Comunicação Interventricular/cirurgia , Adulto , Fatores Etários , Velocidade do Fluxo Sanguíneo/fisiologia , Estudos de Casos e Controles , Ecocardiografia Doppler , Teste de Esforço , Feminino , Comunicação Interventricular/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Função Ventricular Direita/fisiologia
13.
PLoS One ; 15(7): e0236256, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32716984

RESUMO

INTRODUCTION: Previous studies demonstrate increased intracranial pressure (ICP) during direct laryngoscopy in patients with traumatic brain injury (TBI). Worse outcomes in TBI have been associated with increased ICP. It remains unclear if the same effect occurs during cricothyrotomy. We evaluated changes in cerebral blood flow and hemodynamic changes that occurred during preparation for cricothyrotomy in healthy volunteers. METHODS: An emergency medicine trainee performed routine anatomical procedural palpation with simultaneous transcranial doppler (TCD) measurements of cerebral blood flow velocities (CBFV) from bilateral middle cerebral arteries (MCAs). Mean arterial pressure (MAP) and heart rate (HR) were recorded throughout event. Our primary outcome was changes in pulsatility index (PI) and CBFV by TCD during palpation. TCD measurements were used as a surrogate for ICP. RESULTS: We enrolled 20 healthy volunteers for this study. No significant differences were found in pulsatility index [Right MCA -0.02 (95% confidence interval, -0.09 to 0.06), left MCA -0.02 (95% confidence interval, -0.011 to 0.07)] or mean CBFV [right MCA -0.70 mm/s (95% confidence interval, -10.15 to 8.75) left MCA -1.20 mm/s (95% confidence interval, -10.68 to 8.28)] during palpation. No significant change in HR was found [-1.1 bpm ((95% confidence interval, -2.4 to 0.1)]. A change in MAP was observed [1.3 mmHg (95% confidence interval, -0.1 to 2.4)]. CONCLUSIONS: In healthy individuals, no clinically significant change in cerebral blood flow velocities, ICP, or change heart rate was observed during palpation for cricothyrotomy.


Assuntos
Circulação Cerebrovascular/fisiologia , Voluntários Saudáveis , Palpação , Traqueia/fisiologia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Humanos , Masculino , Fluxo Pulsátil
14.
PLoS One ; 15(7): e0231997, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32722669

RESUMO

Human fetal thermoregulation, maternal-fetal heat exchange, and the role of the umbilical cord in these processes are not well understood. Ethical and technical limitations have restricted current knowledge to animal studies, that do not reflect human morphology. Here, we present the first 3-dimensional computational model of the human umbilical cord with finite element analysis, aiming to compute the maternal-fetal heat exchange. By modelling both the umbilical vein and the two umbilical arteries, we found that the coiled geometry of the umbilical artery, in comparison with the primarily straight umbilical vein, affects blood flow parameters such as velocity, pressure, temperature, shear strain rate and static entropy. Specifically, by enhancing the heat transfer coefficient, we have shown that the helical structure of the umbilical arteries plays a vital role in the temperature drop of the blood, along the arterial length from the fetal end to the placental end. This suggests the importance of the umbilical cord structure in maternal-fetal heat exchange and fetal heat loss, opening the way for future research with modified models and scenarios, as the basis for early detection of potential heat-transfer related complications, and/or assurance of fetal wellbeing.


Assuntos
Troca Materno-Fetal , Modelos Biológicos , Cordão Umbilical/irrigação sanguínea , Velocidade do Fluxo Sanguíneo/fisiologia , Simulação por Computador , Entropia , Feminino , Hemodinâmica , Humanos , Gravidez , Pressão , Temperatura , Veias Umbilicais/irrigação sanguínea
15.
Magn Reson Med Sci ; 19(3): 235-246, 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32655086

RESUMO

PURPOSE: To characterize the non-laminar flow dynamics and resultant decreased wall shear stress (WSS) and high oscillatory shear index (OSI) of the infrarenal abdominal aortic dilatation, cardiac phase-resolved 3D phase-contrast MRI (4D-flow MRI) was performed. METHODS: The prospective single-arm study was approved by the Institutional Review Board and included 18 subjects (median 67.5 years) with the dilated infrarenal aorta (median diameter 35 mm). 4D-flow MRI was conducted on a 1.5T MRI system. On 3D streamline images, laminar and non-laminar (i.e., vortex or helical) flow patterns were visually assessed both for the dilated aorta and for the undilated upstream aorta. Cardiac phase-resolved flow velocities, WSS and OSI, were also measured for the dilated aorta and the upstream undilated aorta. RESULTS: Non-laminar flow represented by vortex or helical flow was more frequent and overt in the dilated aorta than in the undilated upstream aorta (P < 0.0156) with a very good interobserver agreement (weighted kappa: 0.82-1.0). The WSS was lower, and the OSI was higher on the dilated aortic wall compared with the proximal undilated segments. In mid-systole, mean spatially-averaged WSS was 0.20 ± 0.016 Pa for the dilated aorta vs. 0.68 ± 0.071 Pa for undilated upstream aorta (P < 0.0001), and OSI on the dilated aortic wall was 0.093 ± 0.010 vs. 0.041 ± 0.0089 (P = 0.013). The maximum values and the amplitudes of the WSS at the dilated aorta were inversely proportional to the ratio of dilated/undilated aortic diameter (r = -0.694, P = 0.0014). CONCLUSION: 4D-flow can characterize abnormal non-laminar flow dynamics within the dilated aorta in vivo. The wall of the infrarenal aortic dilatation is continuously and increasingly affected by atherogenic stimuli due to the flow disturbances represented by vortex or helical flow, which is reflected by lower WSS and higher OSI.


Assuntos
Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma da Aorta Abdominal/fisiopatologia , Velocidade do Fluxo Sanguíneo/fisiologia , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Idoso , Idoso de 80 Anos ou mais , Aorta Abdominal/diagnóstico por imagem , Aorta Abdominal/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
16.
Anesthesiology ; 133(4): 879-891, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32657798

RESUMO

BACKGROUND: Veno-arterial extracorporeal membrane oxygenation therapy is a growing treatment modality for acute cardiorespiratory failure. Cardiac output monitoring during veno-arterial extracorporeal membrane oxygenation therapy remains challenging. This study aims to validate a new thermodilution technique during veno-arterial extracorporeal membrane oxygenation therapy using a pig model. METHODS: Sixteen healthy pigs were centrally cannulated for veno-arterial extracorporeal membrane oxygenation, and precision flow probes for blood flow assessment were placed on the pulmonary artery. After chest closure, cold boluses of 0.9% saline solution were injected into the extracorporeal membrane oxygenation circuit, right atrium, and right ventricle at different extracorporeal membrane oxygenation flows (4, 3, 2, 1 l/min). Rapid response thermistors in the extracorporeal membrane oxygenation circuit and pulmonary artery recorded the temperature change. After calculating catheter constants, the distributions of injection volumes passing each circuit were assessed and enabled calculation of pulmonary blood flow. Analysis of the exponential temperature decay allowed assessment of right ventricular function. RESULTS: Calculated blood flow correlated well with measured blood flow (r2 = 0.74, P < 0.001). Bias was -6 ml/min [95% CI ± 48 ml/min] with clinically acceptable limits of agreement (668 ml/min [95% CI ± 166 ml/min]). Percentage error varied with extracorporeal membrane oxygenation blood flow reductions, yielding an overall percentage error of 32.1% and a percentage error of 24.3% at low extracorporeal membrane oxygenation blood flows. Right ventricular ejection fraction was 17 [14 to 20.0]%. Extracorporeal membrane oxygenation flow reductions increased end-diastolic and end-systolic volumes with reductions in pulmonary vascular resistance. Central venous pressure and right ventricular ejection fractions remained unchanged. End-diastolic and end-systolic volumes correlated highly (r2 = 0.98, P < 0.001). CONCLUSIONS: Adapted thermodilution allows reliable assessment of cardiac output and right ventricular behavior. During veno-arterial extracorporeal membrane oxygenation weaning, the right ventricle dilates even with stable function, possibly because of increased venous return.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Oxigenação por Membrana Extracorpórea/métodos , Modelos Animais , Termodiluição/métodos , Função Ventricular Direita/fisiologia , Animais , Feminino , Pulmão/irrigação sanguínea , Pulmão/fisiologia , Masculino , Suínos
19.
Clin Hemorheol Microcirc ; 76(1): 111-120, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32538827

RESUMO

PURPOSE: The purpose of this study was (1) to compare the effects of ankle pump exercise(APE) frequency on hemodynamics of the common femoral vein(CFV) and (2) to analyse the relationship between APE duration and lower limb fatigue. METHODS: Twenty-seven males and thirty-three females performed APE. Among them, there were thirty participants with non-lower limb fracture (N-LLF) and thirty participants with lower limb fracture (LLF).The colour doppler ultrasound was used to record the time-averaged mean velocity (TAMV) of common femoral venous flow when the participants at rest and move at different frequencies of 6 times/min, 10 times/min, 30 times/min, 60 times/min. The ratings of perceived exertion (RPE) was used to assess the lower limb fatigue of the participants when performing APE at the frequency of 60 times/min after 1 min, 2 mins, 3 mins, 4 mins and 5 mins. RESULTS: With the increase of frequency, TAMV increased significantly in both the participants with N-LLF and LLF (p < 0.01). The TAMV were 19.82±3.86, 33.78±8.76, 37.06±8.67, 43.82±10.40, 52.18±10.53, respectively in the participants with N-LLF and 16.98±3.01, 22.20±4.96, 24.01±5.78, 29.20±7.05, 35.75±9.28, respectively in the injured limb of patients with LLF when at rest and moving at the frequency of 6 times/min, 10 times/min, 30 times/min, 60 times/min. There was a positive correlation (p < 0.01) between lower limb fatigue and exercise duration.When the RPE was 16 points (the corresponding fatigue degree is "tired"), the exercise duration of the participants with N-LLF was 3 mins and that of the injured limb of patients with LLF was 2 mins. CONCLUSIONS: Both fast and slow-frequency APE can promote venous blood return in the lower limb. Despite of the equivalent APE duration, fast-frequency APE can promote venous blood return more effectively. When the frequency of APE was 60 times/min, participants with N-LLF can exercise for 3 mins, and the injured limb of patients with LLF can exercise for 2 mins.


Assuntos
Tornozelo/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Exercício Físico/fisiologia , Hemodinâmica/fisiologia , Extremidade Inferior/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
20.
Ultrasonics ; 108: 106209, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32574828

RESUMO

Undoubtedly, highly valuable information about vascular anomalies is attained by the examination of the blood flow profile. The chief drawback of the conventional medical ultrasound in preparation of the blood periodogram is the measurement system shortcoming at the beam to flow angles near 90°. Recently, a method based on transverse oscillation (TO) approach, known as "Fourth-order estimation", has been developed to directly estimate the transverse power spectral density (PSD) of the fully transverse blood flow. One of the basic requirements to accomplish acceptable PSDs by this technique is the sufficiently large observation window. In this paper, two adaptive approaches for efficient estimation of the velocity spectrum of a fully transverse flow by a limited observation window length are described. The first proposed adaptive approach is based on the minimum variance adaptive spectral estimation in combination with the well-known TO technique (TO-MV). Then, by exploiting the eigenspace separation of the observed data to eliminate the contribution of the undesired components, the second technique (TO-EIBMV) is developed. The approaches are validated using Field II simulations for pulsating flow. The proposed methods are tested and compared to the conventional TO transverse spectral estimator by metrics of relative standard deviation (RSD) and relative bias (RB). One of the main achievements is the decrement of the required data samples for spectrogram estimation, which leads to a better temporal resolution. Moreover, for the analyzed adaptive techniques, the robustness of the estimation results for the beam to flow angles of 60-90° and vessel depths ranging from 20 mm to 60 mm are investigated.


Assuntos
Velocidade do Fluxo Sanguíneo/fisiologia , Artéria Femoral/diagnóstico por imagem , Ultrassonografia/métodos , Simulação por Computador , Humanos , Modelos Cardiovasculares , Fluxo Pulsátil/fisiologia , Transdutores
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